The present invention relates to fuel tanks, and more particularly, to polymeric fuel tanks.
Most fuel tanks are manufactured from stamped metal shell halves. Conventional metal fuel tanks are not only expensive, but they are also relatively heavy and subject to corrosion. In an attempt to avoid the cost, weight, and corrosion problems associated with conventional metal fuel tanks, there is an increasing trend to look toward polymeric fuel tanks.
Polymeric fuel tanks provide a low-weight, corrosion resistant alternative to conventional metal fuel tanks. A particularly ingenious polymeric fuel tank is disclosed in U.S. patent application Ser. No. 07/957,248 filed Dec. 6, 1992 to Hendrik Kleyn. This tank includes a polymeric outer shell surrounding a polymeric inner shell having internal walls that divide the interior of the tank into a series of cells. A fuel absorbent material is located in the space between the inner and outer shells to absorb fuel that might escape from the inner shell.
However, fuel tanks manufactured solely from polymeric materials are subject to permeation and evaporation. To overcome these problems, various composite polymeric constructions have been developed. Composite polymeric constructions have the potential to provide a light-weight, corrosion-resistant alternative to conventional metal fuel tanks.
One such composite fuel tank is disclosed in U.S. Pat. No. 5,129,544 issued Jul. 14, 1992 to Jacobson et al. The Jacobson tank is a laminated construction having an outer layer of abrasion resistant material, such a plastic, Mylar, Teflon, or nylon; a reflective layer of metallic foil; a vapor barrier layer, such as Teflon; a structural layer; and a chemical resistant layer such as Teflon or nylon. The various layers of the tank are bonded together using heat, pressure, and adhesives. The complex laminated structure of this tank is relatively expensive to construct.
A second composite fuel tank is shown in U.S. Pat. No. 4,625,980 issued Dec. 2, 1986 to Lyzohub. The Lyzohub tank has a flexible elastomeric liner fitted within a two-piece metal shell. The elastomeric liner includes a lip trapped between the two pieces of the metal shell. The metal shell of the Lyzohub tank is subject to corrosion and increases both the weight and cost of the tank.